What it means
F31502 reports that the encoder connected as Encoder 1 — an encoder with measuring gear — no longer provides any valid signals, so the drive is no longer receiving usable actual values from this encoder. The manuals classify it under incorrect or unavailable actual position/speed values (message class 11) and describe the code identically for the G130/G150 and S120/S150 families. Depending on how the drive is configured, the same condition can also be issued as an alarm or as a message with no reaction instead of a fault.
Why it appears
- The encoder with measuring gear no longer provides any valid signals, so no usable actual values reach the drive from Encoder 1.
What to check
- Make sure that valid actual values are available in operation. The manual states this as the remedy for this code:
It must be ensured that all of the encoders, with mounted measuring gear, provide valid actual values in operation.
This is the only remedy the manuals give for F31502.
Acknowledging and restarting
The fault must be acknowledged immediately. Once the encoder with measuring gear is delivering valid signals again, acknowledge F31502 and restart the drive; the stopping response the drive executed at the moment of the fault is the one shown in the reaction table for the affected drive object. If the condition is configured to be issued with no reaction (N), the manual specifies NONE both for the reaction and for the acknowledgement — in that case there is nothing to acknowledge.
What differs between the drive families
Straight from the manuals' own fields — F31502 is not described identically everywhere.
| Drive family | Reaction | Acknowledge | Message class | Component | Manual |
|---|---|---|---|---|---|
| S120, S150 | Infeed: OFF1 (OFF2) Servo: OFF1 (OFF2, OFF3) Vector: OFF1 (OFF2, OFF3) Hla: OFF1 (OFF2, OFF3) | IMMEDIATELY | Actual position/speed value incorrect or not available (11) | Sensor Module Encoder 1 | SINAMICS S120, S150 List Manual · p. 3059 |
| G130, G150 | Vector: OFF1 (OFF2, OFF3) Infeed: OFF1 (OFF2) | IMMEDIATELY | Actual position/speed value incorrect or not available (11) | Sensor Module Encoder 1 | SINAMICS G130, G150 List Manual · p. 1744 |
The drives this code lives on
F31502 is described for G130, G150, S120, S150. These are the converters of those families in our catalogue — price on request.
Questions technicians ask
What does fault F31502 mean on a SINAMICS drive?
It reports that the encoder connected as Encoder 1, an encoder with measuring gear, no longer provides any valid signals. The drive therefore no longer receives usable actual values from this encoder.
How do I clear and reset F31502?
Ensure that the encoder with its mounted measuring gear provides valid actual values in operation, then acknowledge the fault immediately. After acknowledgement the drive can be restarted.
Can F31502 also appear as an alarm instead of a fault?
Yes — depending on the drive configuration, the same condition can also be issued as an alarm or as a message with no reaction. As a no-reaction message it causes no reaction and requires no acknowledgement.
Codes next to this one
Source
Written from Siemens' own List Manuals and operating instructions; every number, designation and parameter on this page is checked against them before publication.
All SINAMICS codes: fault and alarm codes · the F31xxx group · SINAMICS manuals · Siemens manuals